Thailand, which has one of the world's largest stateless populations, has granted nationality to just over 18,770 stateless people in the past three years, 4.2 percent of its total, U.N. officials announced Tuesday.

"These figures ... really show the potential for ending statelessness in Thailand," said Ruvendrini Menikdiwela, the representative in Thailand for the U.N. High Commissioner for Refugees.

With 443,862 people still recorded as stateless as of October, the country will need to scale up progress rapidly if it is to meet a U.N. target to end global statelessness by 2024.

Stateless people, sometimes referred to as legal ghosts, are those not accepted as citizens by any country, which means they are deprived of basic rights and are vulnerable to exploitation and traffickers.

Many of Thailand's stateless are from hill tribes, with ancestral ties to their territory and ethnically different from the Thai majority. Others are children of illegal migrants who fled to Thailand, particularly from Myanmar.

Thailand reformed its nationality law in 2008 to address the statelessness problem and has a national strategy to help people acquire citizenship, though the bureaucracy involved is daunting.

Fongchan Suksaneh, a legal adviser to stateless people, said that Thailand's laws were good but that the country was unlikely to end statelessness by 2024.

"The biggest difficulty I come across is corruption and officials themselves not being familiar with the law, and not wanting to be familiar with the law," she said by phone from Bangkok. "When you come up against that mindset, that makes me pessimistic that they'll be able to accelerate [progress] and that they're going to meet the deadline."

The UNHCR said 18,773 stateless people had been granted nationality over three years. Radha Govil, a UNHCR expert on statelessness, said agency officials were very hopeful that the number granted Thai nationality would accelerate "based on the positive momentum so far."

Local Thai officials are increasingly aware that ending statelessness will improve development and reduce poverty in hill tribe areas, where stateless people are often pushed into the drug trade and other illegal activities because they are barred from jobs and their movements restricted, she said.

There are an estimated 10 million stateless people worldwide, with other big populations in Nepal, Myanmar and Ivory Coast. The UNHCR published the Thai figures a year after announcing a global #ibelong campaign to eradicate statelessness within a decade.